Recently, portable telephones have been equipped with multiple functions and are often used as small-sized computers. For example, one example of the functions installed in portable telephones is a data communication function, accompanied with a function of a display device for reading received data such as books, magazines, and newspapers. In the situation in which electronic devices have been frequently used as display devices, there is a demand for further improving electronic devices in terms of usability and visibility.
Patent Document 1 discloses a technology for improving usability and visibility of images displayed on electronic devices. Specifically, Patent Document 1 discloses a portable electronic device equipped with two display screens, which can be opened or closed in a mutual folding direction. A touch panel is attached to the surface of one display screen so as to input an operator command upon being depressed with a finger or a stylus pen, thus performing a process in response to the operator command. For example, it is possible to perform a process in which upon inputting a command to select a certain tab, data displayed on one display screen is transferred to and displayed on the other display screen.